The Senate passed a $5.98 billion supplemental Lend-Lease Bill on October 23, 1941, bringing the United States one step closer to direct involvement in World War II. The Lend-Lease Act, approved by Congress in March 1941, had given President Roosevelt virtually unlimited authority to direct material aid such as ammunition, tanks, airplanes, trucks, and food to the war effort in Europe without violating the nation's official position of neutrality. The supplemental bill brought the amount of available aid to nearly $13 billion. This aid was intended to assist in the defense of nations whose security was deemed vital to the security of the United States. President Roosevelt, who favored U.S. intervention in WWII, advocated creating the program as a way to provide indirect support for the Allies without engaging the U.S. in a war for which there was not yet overwhelming public support.

The United States formally entered the war itself in December 1941, following the Japanese attack on Pearl Harbor.

Initially created to help Great Britain, within months, the Lend-Lease program was expanded to include China and the Soviet Union. By the end of the war, the United States had extended over $49 billion in Lend-Lease aid to nearly forty nations.